It really depends on what you want to accomplish. First off, if you haven't trained specifically in MMA I would suggest atleast a solid year of training before you even take an amateur fight. Too many guys (kids) want to jump right in the ring/cage and start fighting. They usually do so with little training and they end up getting hurt. With that said, you can definately start out training part time by just getting in shape, lifting, stretching, hitting the bags and grappling (even if it is with your step-son). However, you will soon need more. You need atleast a competent trainer to start some "real" training with. MMA is an art. There are so many disciplines to learn AND you have to be able to put them all together. This takes time and lots of it. But, if you want to do it, do it! I am 36 years old, married and have 3 children (10, 7 & 2). Somehow, I manage to do cardio 5 days per week, lift 3 days per week and train 3 days per week. I will probably have my first professional fight this year around May/June. 99% of everybody on here will tell me I am too old for this sport. But, I want to do it, so guess what? I'm going to do it! So, if you want to do it, then do it! My suggestion is to just be smart and don't get impatient. Find somewhere to train and learn all you can. If you like it and want to fight, then set your self a goal of when you want to fight. Find someone in the business that can set you up a "starter" fight and then train your butt off. You usually figure out if you want to do this while training or during your first fight, lol. Either way, have fun and good luck!